Electrical connection



March 20, 1934- J. LE R-JOHNSON ET AL ELECTRICAL CONNECTION Filed Nov.22, 1932 2 Sheets-Sheet 2 FIE-E.

attorneys.

Patented Mar. 20, 1 934 UNITED STATES 1,951,981 ELECTRICAL CONNECTIONJustus Le Roy Johnson, Lynwood, and Martin Geiszler, South Gate, Calif.

Application November 22, 1932," Serial No. 643,942

1 Claim.

the like being placed in the receptacle and cansing short circuits.

A further object is to produce a device wherein the standard practice ofscrewing a plug or bulb into a receptacle is maintained.

A still further object is to produce a device which will not materiallyincrease the cost of manufacture.

Other objects and advantages will be apparent during the course of thefollowing description.

In the accompanying drawings forming a part of this specification and inwhich like numeralsare employed to designate like parts throughout thesame, v

Fig. 1 is a cross sectional view of a wall type receptacle having a bulbpositioned therein.

Fig. 2 is a fragmentary cross sectional view of the receptacle with thebulb removed,

Fig. 3 is a top plan view of the receptacle threaded element,

Fig. 4 is a side elevation oi Fig. 3, I

Fig. 5 is a view similar to Fig. 1; but showing a key type receptacle,

Fig. 6 is a side elevation of a bulb,

Fig. '7 is a sectional view of a keyless type re-' ceptacle, and

Fig. 8 is a perspective cross sectional view of a v plug for use withthereceptacle.

The ordinary receptacle has positioned therein a threaded element forengaging the stem of a bulb and a contact against which the end of thebulb engages. This contact and threaded element are each electricallyconnected to opposite sides of the power line and as a result the personcan insert the fingers or a metal object into the receptacle and receivea shock or cause a short circuit, often-times with serious results. Withour device this is impossible.

Referring to the drawings, and'particularly to Fig. 1, it will be notedthat an insulated base 5 block 5 carries a bus bar 6 which iselectrically connected to a line wire 7. A contact 8 is electricallyconnected to a line Wire 9. A cover block 11 is secured to the base Sandhas a chamber 12 in which an insulating support 13 is positioned:

The cover block has an upstanding portion 14 which serves to house athreaded element 16 having a flange 17 provided with spring fingers 18.These spring fingers contact a shoulder 19 formed upon the cover blockand to therefore normally hold the threaded element in'the positionshown in Fig. 2. This threaded element has an open ing therethroughwhich has parallel sides (see Fig. 3) Within this opening is positioneda guide block 21, which rests upon the support 13 and is securedthereto. This guide block has parallel sides and therefore prevents thethreaded elements 16 from rotating, but permits the same to slidethereon in a manner to be later described. Mounted within a bore formedin the guide block and support 13 is a spring pressed pin 22, held inthe position of Fig. 2 by a spring 23.

In the form shown in Figs. 5 and '7 the construction is the same withthe exception that the base block 5 is positioned within a receptaclecasing 24 which casing of course is lined with insulation 26. Thiscasing also surrounds the threaded element 16, which threaded element isnormally held down by a spring 27 surrounding the guide block 21. The'action of the spring 27 is similar to the action of the spring fingers18. The key switch is designated as a whole by the numeral 28. As theremaining parts are identical the same numerals apply as those employedin describing Figs. 1 and 2. v

Referring to Fig. 6 it will be noted that the bulb 29 has a metal screwthreaded element 31 and an insulating projection 32, which carries acontact 33, and by referring to Fig. 8 it will be noted that the plug 34has a threaded element 36, an annular recess 35 and an insulatingprojection 3'7, which projection carries a contact 38,

-which contact is electrically connected by a wire 39 to a contact clip41 and that the threaded element 36 is connected by a wire 42 to acontact clip 43. a

The result of this construction is that, assuming that the parts are inthe position of Fig. 2, the threaded elements 16 will be held down uponthe support 13 and consequently the flange 17 will be out of contactwith the contact 8. At the same time the spring 23 will be holding thepin 22 in an elevated position and consequently its lower end will beout of engagement with the bus bar 6. When a bulb or a plug such asshown in Figs. 6 'or 8, respectively, is inserted in the receptacle, thescrewing in of the bulb or the plug will result in thecontact 33 at theend of the insulating projection 32 of the bulb or contact 38 at the endof the insulating projection 37 of the plug, forcing the pin 22downwardly against the tension of the spring 23 and into engagement withthe bus bar 6, and at the same time pulling upwardly the threadedelement 16 which rises upon the guide block against the tension of thespring fingers 18. Thereafter the flange 17 will be brought into contactwith the contact 8, thus establishing a circuit from the bus bar 6,through the bulb and to the contact 8, for it is to be noted that thebus bar and contact are electrically connected to a source of energy. Itwill be apparent that the bulb will be energized or that the plug willbe capable of delivering current as soon as a connection is madetherewith. As soon as either the bulb or plug are removed the parts willreturn to their inoperative position of Fig. 2 and consequently thesocket will be dead as far as the possibility of receiving a shocktherefrom or short circuiting thereof, is concerned.

It is to be understood that the form of our invention herewith shown anddescribed is to be taken as a preferred example of the same and thatvarious changes relative to the material, size, shape and arrangement ofparts may be resorted to without departing from the spirit of theinvention or the scope of the subjoined claim.

Having thus described our invention, w claim:

In a device of the character described, a supporting block, a guideblock positioned on said supporting block, a threaded element movable onsaid guide block, resilient means carried by said threaded element fornormally maintaining said threaded element against said supportingblock, means for preventing rotation of said-

